Vocab and more about Muscle Contractions

Sarcolemma

Muscle fiber

Endomysium

Perimysium

Muscle fascicle

Epimysium

Skeletal muscle

Epimysium (Where, what is it made of, what does it surround?)

Outside the muscle

Surrounds ENTIRE skeletal muscle

Dense irregular connective tissue

Perimysium (Where, what does it do, what is it made of)

“Around muscle

Separates adjacent muscles

Fibrous connective tissue

Endomysium (Where, what does it do, what is it made of)

“Within the muscle”

Surrounds SINGLE muscle fiber

Areolar connective tissue

Sarcolemma

Cell membrane of muscle fiber

Sarcoplasm

Cytoplasm of muscle fiber

Lots of

Mitochondria

Glycosomes

Carry stored glycogen

Myoglobin

Stores oxygen

Myofibrils

Contain contractile elements

Sarcoplasmic reticulum

Elaborate smooth endoplasmic reticulum

Around each myofibril

Regulates levels and storage of calcium

T Tubules

Extension of Sarcolemma

When AP is in it - causes realease of calcium by sarcoplasmic reticulum (muscle contraction)

Myofibril

Organized collection of myofilaments

Myofilaments

Fine protein filaments

H Zone

Z line

I band

A band

Thin filament

Actin

Thick filament

Myosin

Tropomyosin

Binds to active site of actin at rest

Troponin

Binds to tropomyosin and calcium - causes contraction

Motor Unit

Motor neuron and all the muscle fibers it innervates